Rock music has always had its critics and those that wish that rock and pop would just go away. But over the years it has proven to be pretty resilient and has withstood the test of time. Pop is a bit of a different animal than rock despite the two genres do tend to cross over a great deal. It's usually classified as driven by electric guitar and all the various sub-genres of rock are usually identified with electric guitar driven music. It also usually has a certain angst or message to it and many in this industry take their music and their message very seriously.
On the other hand, Pop is usually a little more encompassing than rock music. It's used to identify music that seems to be universally popular with a large audience and can cross over from genre to genre. Another aspect is that it is accepted as being short for popular so what we are really dealing with here is what the music industry subscribers to be popular which translates into music that has greater potential to sell a lot of records. It is also designed to be catchy to the ear and grab a large audience right away. Many new country artists are beginning to write songs that are country but are also being classified as pop because of their universally catchy hooks.
Sometimes pop can create other genres due to the growing popularity of the music within the it's genre. Disco was similar until it evolved into its own music style and became very popular in the 1970's. Hip Hop is a mixing of rap and pop music that has become an extremely popular sub-genre and stands today as one of the most popular in the industry.
But rock music always looks to be there whether it is in the background as it was in the 1980's or in the foreground as it was in the 1960's and seems to be again today. It seems to work in cycles and those cycles are completely influenced by the popularity of pop music at the time.
It seems that there is a large audience within the music industry that likes to jump from one genre to the next and that audience is the one that creates the pop music crazes that rule from year to year and that audience also dictates when rock music is at its peak and when rock seems to be in decline. In the days when Britney Spears and Christine Aguilera were at the peak of their popularity pop music was at its peak which cause people to lose interest in rock. Artists such as Pearl Jam and Metallica seemed to lose their luster and their record sales shifted to those acts offering a more pop sound.
Today acts like The White Stripes and The Killers are starting to bring rock back to the forefront and it will not be long before rock it's giving hip hop and other forms of pop a run for their money.